Question 327: Question : If someone is traveling on a plane & time of prayer falls within his/her travel time, what will be the direction of Qibla he/she should turn his/her face for salat? According to me, usually Qibla will be downwards (but not east, west, north or south) when you are on a flight….so do you know what is the ruling of major marja-e-keram about this? How offering prayers on a plane should be toward Qibla?
Answer 327: Under no circumstances or conditions is it permissible to discard Salah, as it is wajib. Salah must be offered in any possible situation. If possible, a person who is in flight, space, or any other means of travel should try to settle in a fixed location using the available means in order to complete salah. If a person cannot do that, then they should offer their salah in any way possible, even if they can only use motions.
If the one stands facing towards earth, then they are facing the Qibla and they should pray in that direction, but if they could not distinguish the earth’s position, then they must pray in all four directions (if possible). If all directions are not possible, then they must pray in as many directions as possible.
As far as wudhu goes, if they can or if it is possible then they should make wudhu. If it is not possible to make wudhu then they should make tayamum. If making tayamum is also not possible, then they should take precaution and make salah without wudhu or tayamum, but later they should make up the Qaza prayers for the salah which was performed without wudhu or tayamum.
In addition, regarding complete salah vs. traveler’s salah: if an astronaut were to know that they were going to stay in one area of space for at least ten days then they should make his salah complete. In any other instance, they should shorten their salah. If being an astronaut is a persons occupation, then as long as after the first trip, they don’t stay in his hometown or outside of his hometown for more than ten days, then on their second trip their his salah will be complete. If however, they were to stay in his hometown or other than his hometown for ten days or more, then if they traveled to space again, they would have to shorten their salah.
In reply to this question that how can we say our obligatory prayers in an aircraft, especially if we do not know the direction of the qiblah taking into consideration the instability of the floor [because the plane is in motion]? Sayyid Sistani (ha) answers: As for the qiblah, it is possible to identify its direction by asking the captain or the airhostesses because their answers usually carry validity and are a source of assurance. One should therefore act accordingly.
As for the stability of the floor where salat is to be performed, that condition will be waived when it is not possible to achieve it. However, other conditions of prayers should, wherever possible, be observed. Under no circumstance should the prayer be delayed beyond its appropriate time span.
 . Imam Khomeini (May Allah have mercy on his soul), Istiftaat, Questions: 28&29; Tawzihul Masael of maraja’, Vol. 1, Pg. 434, Question 784.
 . Tawzihul Masael of maraja (with annotation of Imam Khomeini), Vol. 1, Pg. 381, Question 686; Ibid, Question 339.
 . Ibid, Vol. 1, Pg. 705, Question 1312.